Sonicwall suddenly blocking VPN access

After my client rebooted their Sonicwall none of the users can connect to the Windows PPTP VPN anymore. It seems like Sonicwall thinks the VPN is trying to connect to it instead of the Windows server. The Sonicwall logs display the following:

Info VPN IKE IKEv2 Responder: Received IKE_SA_INIT request
Warning VPN IKE IKEv2 VPN Policy not found
Warning VPN IKE IKEv2 Payload processing error